陈陈相因（陳陳相因）　

◎ 陈陈相因 chénchén-xiāngyīn

[follow a set routine;do sth in a conventional way] 仓中粮食逐年累加,久而不食,则变为陈粮。后以此比喻处理问题因袭旧法,毫无改进